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As a result of climate change, forest fires are becoming a common factor in the dynamics of ecosystems in the forest zone of Ukraine, but the assessment of the consequences of this shift in the ecological situation is in the process of pilot studies. In the spring of 2020, a number of large ecosystem fires occurred in the Central Polissia region, which affected forests the most. Among other things, a large fire occurred in ecosystems located in the Exclusion Zone and the Zone of Unconditional (Mandatory) Resettlement, which was formed as a result of the Chornobyl accident. The ecosystems of the Chornobyl Radiological and Ecological Biosphere Reserve located within its boundaries were also affected by the fire. The consequences of this fire were assessed a year later, using mouse-like rodents as a model group. The purpose of the study was to assess and compare the communities of mouse-like rodents in areas that were affected by two degrees of fire damage—where there was a surface fire and those that were most affected (highland fire). Four polygons were created in the control-impact scheme. Each of the pairs of plots was identical in terms of typical forest vegetation conditions. Sherman traps were used for trapping. A total of 560 trap-days were processed, and 101 animals were captured. The presence of four species of rodents from the genera Apodemus, Sylvaemus, and Myodes was recorded, namely the striped field mouse, the yellow-necked wood mouse, the European wood mouse, and the bank vole. The main indicators of species diversity were calculated using information indices—species richness, evenness, and similarity. The surveys revealed both negative and positive changes in areas affected by fires. Areas characterised by relatively higher values of species diversity indices compared to the control had a high intensity of vegetation recovery. They belonged to areas with wet, relatively fertile (sugrud) and infertile (subor) forest types. The plots with low intensity of vegetation recovery had a depleted community structure and belonged to fresh and dry boreal forest. Based on this, it is possible to create a forecast of ecosystem restoration by assessing the type of forest vegetation conditions.

Methods for dose estimation of 137Cs in mouse-like rodents, specifically bank voles (Myodes glareolus), commonly found within the research sites in the Chornobyl Exclusion Zone, are being proposed. The International Commission on Radiological Protection recommends using the specially developed "BiotaDC" software, but it needs to be adapted to solve specific applied issues. It is shown that the "BiotaDC" approach adequately describes dose accumulation of 137Cs for external exposure inside nest chambers if the mean integral value of soil activity concentration at a depth of 0.5 m is used, for external exposure above soil – if the mean integral value of soil activity concentration at a depth of 0.2 m is used. However, the authors propose a method considering the age of animals at the time of capture and the age-related dynamics of changes in such parameters as excretion and accumulation of radioisotopes for internal dose estimation using the "BiotaDC" software. A detailed dose estimation algorithm is being proposed. Dose estimates for internal irradiation according to the authors' method and the method of the International Commission on Radiological Protection are being compared.

Methods for dose estimation of 137Cs in mouse-like rodents, specifically bank voles (Myodes glareolus), commonly found within the research sites in the Chornobyl Exclusion Zone, are being proposed. The International Commission on Radiological Protection recommends using the specially developed “BiotaDC” software, but it needs to be adapted to solve specific applied issues. It is shown that the “BiotaDC” approach adequately describes dose accumulation of 137Cs for external exposure inside nest chambers if the mean integral value of soil activity concentration at a depth of 0.5 m is used, for external exposure above soil – if the mean integral value of soil activity concentration at a depth of 0.2 m is used. However, the authors propose a method considering the age of animals at the time of capture and the age-related dynamics of changes in such parameters as excretion and accumulation of radioisotopes for internal dose estimation using the “BiotaDC” software. A detailed dose estimation algorithm is being proposed. Dose estimates for internal irradiation according to the authors’ method and the method of the International Commission on Radiological Protection are being compared. [ABSTRACT FROM AUTHOR]

The results of radioecological monitoring of the research sites located on the drained areas and the coastal of the ChNPP cooling pond are presented. The features of the spatial distribution of the exposure dose rate, the density of soil radionuclide contamination by the emergency radionuclides were determined. The content of incorporated radionuclides in representatives of the genera Myodes and Sylvaemus were studied, the individual and interspecies variability of 137Cs and 90Sr levels in animals within the limits of one research site was determined. Currently, the indicators of radioactive contamination of biota in the drained areas of the cooling pond are within the variation of those values that are characteristic of most areas of the Chornobyl exclusion zone.

Studies of radiobiological effects in murine rodents exposed to internal radiation in the wild or in laboratory experiments require dosimetric support. The main problem of bone marrow (BM) dosimetry for bone-seeking β-emitters is dosimetric modeling, because the bone is a heterogeneous structure with complex microarchitecture. To date, there are several approaches to calculating the absorbed dose in BM, which mostly use rough geometric approximations. Recently, in the framework of studies of people exposed to 90Sr in the Urals, a new approach (SPSD) has been developed. The aim of the current study was to test for the first time the possibility of extension of the SPSD approach elaborated for humans to mice. For this, computational phantoms of femur bones of laboratory animals (C57BL/6, C57BL/6 J, BALB/c, BALB/cJ) aged 5–8 weeks (growing) and > 8 weeks (adults) were created. The dose factors DFSr-90(BM ← TBV + CBV) to convert the Sr isotope activity concentration in a bone tissue into units of dose rate absorbed in the bone marrow were 1.75 ± 0.42 and 2.57 ± 0.93 μGy day−1 per Bq g−1 for growing and adult animals, respectively, while corresponding values for DFSr-89(BM ← TBV + CBV) were 1.08 ± 0.27 and 1.66 ± 0.67 μGy day−1 per Bq g−1, respectively. These results are about 2.5 times lower than skeleton-average DFs calculated assuming homogenous bone, where source and target coincide. The results of the present study demonstrate the possibility of application of the SPSD approach elaborated for humans to non-human mammals. It is concluded that the study demonstrates the feasibility and appropriateness of application of the SPSD approach elaborated for humans to non-human mammals. This approach opens up new prospects for studying the radiobiological consequences of red bone marrow exposure for both laboratory and wildlife mammals. [ABSTRACT FROM AUTHOR]

The results of radioecological monitoring of the research sites located on the drained areas and the coastal of the ChNPP cooling pond are presented. The features of the spatial distribution of the exposure dose rate, the density of soil radionuclide contamination by the emergency radionuclides were determined. The content of incorporated radionuclides in representatives of the genera Myodes and Sylvaemus were studied, the individual and interspecies variability of 137Cs and 90Sr levels in animals within the limits of one research site was determined. Currently, the indicators of radioactive contamination of biota in the drained areas of the cooling pond are within the variation of those values that are characteristic of most areas of the Chornobyl exclusion zone. [ABSTRACT FROM AUTHOR]

Background. The study of morphological, genetic and environmental factors explaining the subdivided (metapopulational) structure of habitats is a new and methodologically poorly developed scientific field. An important part of such research is the study of the genetic structure of animal populations. This scientific field is aimed at solving fundamental biological problems: the integrity of the biological species, microevolution and intraspecific differentiation, and population dynamics. The purpose of the work is to study the ecological characteristics of genetic polymorphism of Herb Field Mouse (Apodemus uralensis Pallas, 1811), Striped Field Mouse (Apodemus agrarius Pallas, 1771) and Yellow-necked Field Mouse (Apodemus flavicollis Melchior, 1834) mice in the Middle Volga region on the example of the Ulyanovsk region. Materials and methods. The genetic material for the work was collected in the Ulyanovsk region during field work over the period from 2014 to 2018. A total of 33 sequences (699 bp) of wood mice, 14 sequences (623 bp) of field mice and 9 sequences (700 bp) of yellow-necked mice were analyzed. For this, the MEGA 7.0.21 and DnaSP 5.10 software packages were used (Librado and Rozas, 2009; Tamura et al., 2012). In order to identify the environmental patterns of the distribution in the Ulyanovsk region of populations of the studied species of mouse-like rodents, except population groups obtained from data on their geographical proximity, we used two variants of zoning of the region under study- floristic and ecologicallandscape. Results. The highest level of variability of mitochondrial D-loop fragments was detected in A. flavicollis (2.4 ± 0.3%), while this indicator for A. uralensis and A. agrarius had average values (0.8 ± 0.2% and 0.7 ± 0.2%, respectively). Analysis of sequence samples by geographically selected population groupings did not reveal the corresponding genetic differentiation. Distribution of the identified mitotypes by population groupings does not have any pattern. Mitotypes found only in one of the groupings are present in the samples, and for this reason they are specific. The same results were obtained when analyzing the distribution of the identified mitotypes by floristic zoning of the Ulyanovsk region. The distribution of the identified mitotypes by landscapeecological regions reflects the ecological requirements of the studied species of mouse-like rodents. Conclusion. The results obtained indicate a good resolving power of the developed primer systems for amplifying D-loop and studying populational polymorphism of natural populations, as well as for grouping geographically separated populations of mouse-like rodents. The study of the distribution of the identified mitotypes of all three species of mouse-like rodents according to the floristic regions of the Ulyanovsk region did not reveal any connection between the floristic specificity of the territories and the distribution of these rodents in the region. This is probably due to the fact that the criteria for floristic zoning do not correlate with the biotopic preferences of the studied species. The distribution of the identified mitotypes by landscape-ecological regions, on the contrary, is in good agreement with the environmental requirements of the three species of mouse-like rodents. The D Tajima test for three species of mice in the Ulyanovsk Region indicates a possible increase in the number of their populations after going through the “bottleneck” during the period of population decline. This synchronization of demographic processes in populations of these species of mouse-like rodents is probably associated with a strong fragmentation of the habitat observed in the Ulyanovsk region, and high degree of subdivision of local populations of rodents.

Based on the results of retrospective analysis of HFRS morbidity and epizootiological data on the numbers and contamination of mouse-like rodents, revealed has been epidemic potential shift of the HFRS foci. It requires reconsideration of the scope, format, and objectives of preventive and anti-epidemic activities. Periodicity of fluctuations in the numbers of small mammals, habitant in the territory of the Ulyanovsk Region, makes up three years on average. Since 2011 up to 2013 generalized depression in the abundance rates was observed. The period was marked by the reduction of the segment of main Hantavirus carrier - common red-backed vole. It was the key factor for epidemic process activity decrease, which in its turn resulted in the decrease of morbidity rates among the population. Therewith, the transformations that affect the population of mouse-like rodents are the determinative factors in the evolution of epidemic process which shapes epidemiological situation on HFRS in the territory of the constituent entity.

The article discusses the morphophysiological and behavioral 'congruences' that determine relationships in family triads between mother and offspring, females and males, and same-sex members. The role of congruences in the realization of reproductive potential and the development of adaptability in offspring is analyzed and discussed with respect to data obtained in small Siberian rodents through natural monitoring and laboratory investigation. [ABSTRACT FROM AUTHOR]

The role of the background species of mouse-like rodents in the preservation of arboviral infections in the semi-desert zone of Saratov Zavolzhie was studied. Determined were the indices of their number in the near-water and anthropogenic biotopes, and arboviral infection rate in some species. Substantiated was high potential epidemic danger of the intrazonal biotopes as centers of formation of associated natural foci of arboviral infections.

A method assessing one of the several types of investigative behavior was used to study the existence of forelimb motor asymmetry in three species of mouse-like rodents from natural populations of different families: the striped field mouse ( Apodemus agrarius) from the mouse family ( Muridae) and the bank vole ( Clethrionomys glareolus) and northern redbacked vole ( Cl. rutilus), which are two closely related species of the hamster family ( Cricetidae). Animals were selected from different populations whose habitats were significantly different in terms of food and protective conditions, the levels and types of anthropogenic pollution, and local biota. All species showed a predominance of right-sided asymmetry in animals of both genders. Spatial and temporal variability of asymmetry profiles was demonstrated. An increase in the proportion of 'left-handers' was seen in biotopes in which animals experienced increased adaptive pressure. The ratio of 'right-handers' to 'left-handers' (right/(left + ambidextrous) animals) in rodent populations was not constant, but oscillated with a periodicity (2-3 years) close to the dynamics of population numbers. It is suggested that this ratio in populations of individuals with motor asymmetry of different signs facilitates the maintenance of population homeostasis. [ABSTRACT FROM AUTHOR]

The composition and structure of mouse-like rodent communities in altitudinal belts of the Kuznetsk Alatau Mountains are studied, and their comparative characterization is made. It is shown that the complex altitudinal-zonal differentiation of the mountain range leads to the formation of several types of mouse-like rodent communities: forest-steppe, dark coniferous-taiga, chern forests, and mountain tundra. The communities differ in species composition, structure, and total number. The main factors influencing the spatial distribution of species and their number are hydrothermal conditions, vegetation type, and anthropogenic transformation of the territory. [ABSTRACT FROM AUTHOR]

Morphofunctional analysis (morphological and stereological) revealed stereotypic morphofunctional reactions (hemodynamic disturbances accompanied by considerable cardiomyocyte degeneration) in the myocardium of common field mice and common voles from various Altai regions. Changes in the capillary surface-volume ratio and the stroma/parenchyma volume ratio are typical of tissue reorganization of the myocardium. The nature of these changes depends on the level and type of contamination. [ABSTRACT FROM AUTHOR]